Martina's versatility attracted Koeman to the Curacao international, who made nine Premier League appearances for Southampton last season, as Everton attempt to balance European commitments with their efforts to break into the Premier League's top six.

"Cuco Martina is an experienced player who can perform in different positions at the back, which is important," Koeman said. "It's also important, with the number of games we will face in the coming campaign, that we have strength and competition in the squad.

"I brought the player to Southampton, so I know what he can do for us here and this is why I've now brought him to Everton. He is a player who will strengthen our squad and be able to play in different positions when that's needed, too."